Please note that while you can access your library through the Zotero website, all of the useful features of Zotero work only with the desktop version.
While this guide covers the basics of how to set up and use Zotero, you can read about the new features added as part of Zotero 7.
Once you've validated your email address and installed the tool on your computer, Zotero will ask you to finish setting up your preferences.
It's important to link the Zotero library on your computer with your online account. That way, any changes you make to your local Zotero library will be automatically synced with your library in the cloud.
The Zotero plugin for Microsoft Word or LibreOffice should also install as part of this process if you have either of those already. To verify it installed correctly in Word, open a Word document and look for the Zotero tab in the top main bar in Word. If this doesn't happen, you can manually install it from within your Zotero library.